'Optical Battery' Discovery Could Mean Solar Power Without Solar Cells

Researchers at the University of Michigan have made a scientific discovery that is intriguing all on its own but it is the breakthrough’s potential applications in solar power generation that have them excited.

According to Stephen Rand, a professor at the university and author of the paper that discusses his team’s discovery in the “Journal of Applied Physics”, the researchers found a way to make an “optical battery” which harnesses the magnetic attributes in light that, until now, scientists didn’t think amounted to much of anything.

The report explains that light has both electric and magnetic components but, until now, scientists believed the magnetic field effects were weak enough that they could be ignored. Rand and his fellow researchers, however, found that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than thought possible. Under these circumstances, says Rand, the magnetic fields become similar in strength to a strong electric effect.

William Fisher, a doctoral student in applied physics, says that what makes this possible is “a previously undetected brand of “optical rectification.” In traditional optical rectification, light’s electric field causes positive and negative charges to be pulled apart in a material. That sets up voltage, similar to a battery.

Before, this effect had only been observed in crystalline materials that possessed a certain symmetry. This process works with materials such as glass, but presently requires light that surpasses the sun’s natural intensity. Fisher indicated they were working on finding materials that would work at lower light intensity.

The research team believes that this discovery could lead to a solar cell that requires no semi-conductor. Since semi-conductors constitute a bulk of a solar cell’s processing, eliminating it represents an opportunity for a considerable reduction in costs.

Fisher notes that a solar cell using this new energy harvesting technique would only require lenses to focus the light and fiber to carry it. “Glass works for both,” said Fisher, ”it’s already made in bulk, and it doesn’t require as much processing. Transparent ceramics might be even better.”